Rock Island State Park is a state park of Wisconsin located on Rock Island off the tip of the Door Peninsula at the eastern edge of Green Bay and Lake Michigan.
History
Rock Island was proposed as a state park in early 1961 by officials of the Town of Washington Island, particularly Jack Hagen the town chairman.
A feasibility study was made in September 1961 by the Wisconsin Department of Conservation. A group of people including Jack Hagen and other town officials, some county officials, and some state officials along with Lawrence Johnson walked around and flew over the island to consider it. The county board approved the acquisition on December 11, 1961.
Activities and amenities
Attractions include the stone Viking boathouse and other structures including a historic water tower built by inventor Chester H. Thordarson in what is now known as the Thordarson Estate Historic District, Native American artifacts, as well as Pottawatomie Light, which is Wisconsin's oldest lighthouse. The island is a destination in the fall for deer hunters and in the winter for snowmobilers from nearby Washington Island. The park has campsites available and is a destination for day trippers.
Transportation
The only public transportation to the island is by the passenger ferry Karfi from Washington Island. However, there is mooring and dock space for people with their own boats, and during winter the island is accessible via snowmobile and foot traffic. No "wheeled vehicles" (cars, all-terrain vehicles, bicycles) are allowed to be brought onto the island by visitors, although park staff use them routinely.
Climate
The climate of Rock Island is moderate with an annual mean temperature of . The average annual number of frost-free days is approximately 145 on nearby Washington Island, where basic climatic data is recorded for the region. Recorded temperatures range from a low of to a high of . The mean annual precipitation is approximately 28 inches, with an average winter snowfall totaling fifty inches. The immensity of the surrounding body of water generally insulates Rock Island and its neighbors from the extremes of summer heat and winter cold that is experienced in the interior parts of the country at this same latitude. Moderating effects of the waters also prolong cold weather in the spring and repress early frosts in the fall. The worst storms to hit Rock Island generally occur in the autumn and are driven by winds from the northwest.